Primary Staging of Prostate Cancer Patients with [(18)F]PSMA-1007 PET/CT Compared with [(68)Ga]Ga-PSMA-11 PET/CT

Background: Hybrid imaging with prostate-specific membrane antigen (PSMA) is gaining importance as an increasingly meaningful tool for prostate cancer (PC) diagnostics and as a guide for therapy decisions. This study aims to investigate and compare the performance of [(18)F]PSMA-1007 ((18)F-PSMA) and [(68)Ga]Ga-PSMA-11 positron emission tomography/computed tomography ((68)Ga-PSMA) in the initial staging of PC patients. Methods: The data of 88 biopsy-proven patients were retrospectively evaluated. PSMA-avid lesions were compared with the histopathologic Gleason Score (GS) for prostate biopsies, and the results were plotted by receiver operating characteristic (ROC)-curve. Optimal maximum standardized uptake value (SUV(max)) cut-off values were rated using the Youden index. Results: (18)F-PSMA was able to distinguish GS ≤ 7a from ≥7b with a sensitivity of 62%, specificity of 85%, positive predictive value (PPV) of 92%, and accuracy of 67% for a SUV(max) of 8.95, whereas sensitivity was 54%, specificity 91%, PPV 93%, and accuracy 66% for (68)Ga-PSMA (SUV(max) 8.7). Conclusions: Both methods demonstrated a high concordance of detected PSMA-avid lesions with histopathologically proven PC. (18)F-PSMA and (68)Ga-PSMA are both suitable for the characterization of primary PC with a comparable correlation of PSMA-avid lesions with GS. Neither method showed a superior advantage. Our calculated SUV(max) thresholds may represent valuable parameters in clinical use to distinguish clinically significant PC (csPC) from non-csPC.